Similar to StaticFileSet, but uses Portage configuration files.
Namely it can work with package.use,
package.keywords, package.mask
and package.unmask. It does not support
.metadata files, but ignores the extra data (like
USE flags or keywords) typically found in those files.
In a single set configuration this class supports the following options:
filename: See
StaticFileSetStaticFileSet
In a multi set configuration this class supports the following options:
directory: Optional, defaults to
/etc/portage. Specifies the path to a directory
containing one or more of the following portage configuration files:
package.use, package.keywords,
package.mask or package.unmask.
No other files in that directory will be used.
name_pattern: Optional, defaults to
package_$suffix. This describes the naming
pattern to be used for creating the sets. It must contain either
$suffix or ${suffix},
which will be replaced by the file suffix (e.g.
use or mask).